China has warned that Washington's announcement of arms sales to Taiwan would badly hurt ties between the two global powers, widening rifts in their far-reaching relationship.

The swift and sharp protest came from Chinese Vice Foreign Minister He Yafei, who said his government was "strongly indignant" about the proposed US sale of weapons to Taiwan, which China considers an illegitimate breakaway province.

Beijing responded with He's warning delivered to the US ambassador to China, Jon Huntsman, that the arms deal could jeopardise bonds with Washington, which has looked to China for help in surmounting the financial crisis, dealing with Iran and North Korea, and fighting climate change.

The US arms sales to Taiwan have joined trade imbalances, currency disputes, human rights, the Internet, and Tibet among rifts dividing the world's biggest and third-biggest economies.

Washington and Beijing have also recently traded angry words about Internet policy after the search engine giant Google Inc earlier this month threatened to shut its Chinese google.cn portal and pull out of China, citing censorship problems and hacking attacks.

Vice Minister He did not spell out what reprisals Beijing may mete out against Washington over the weapons sales. But he hinted the anger would be felt in a number of areas.

"The United States' announcement of the planned weapons sales to Taiwan will have a seriously negative impact on many important areas of exchanges and cooperation between the two countries," said He in the remarks, published on the Chinese Foreign Ministry's website.

He said the arms sales were "crude interference in China's domestic affairs and seriously harm China's national security", words notably tougher than Beijing's recent statements on the issue.

"This will lead to repercussions that neither side wishes to see," said He. He urged the US to halt the planned sales.